If you are a WordPress developer and want to upgrade or take your skills to the next level, there are top 10 resources to help you in addition to the powerful WordPress Codex.
One of the key elements of the WordPress boom is its user community.
By looking around, you will find solutions to almost every problem.
Below we try to compile a list of useful resources that will guide you through the use of excellent WordPress and increase the speed of production.
1. QueryPosts
An excellent code reference site for WordPress developers, it extends a lot of useful information for WordPress Codex. QueryPosts provides detailed WordPress code references with information such as descriptions, signatures, sources, and links to trac and github. Currently, it provides references to 1996 functions and plans to add references to classes and hooks. Thanks to Andrey Savchenko for providing this impressive resource and making life easier for a WordPress developer.

2. Hookr
A wonderful project by Christopher Sanford. It lists information about all available WordPress hooks and API calls. Hookr currently holds references to actions, filters, classes, constants, functions, and shortcodes.

3. The WP Hooks Database
This includes information on WordPress action hooks and filter hooks. If you would like to see the full list of all the hooks and their version numbers at the same time, please visit this website.

4. WPSeek
It started as a WordPress plugin for Firefox but later evolved into a WordPress feature, filter, action, and constant search engine. You can browse functions or search functions by keywords. Recently, WPSeek creator Oliver Schlobe released the WPSeek Android app to find WordPress features on the go.

5. 10up Engineering Best Practices
This in-depth guide covers everything from efficient database queries, data storage, namespaces and security to useful tools for local development, dependency management, version control, PHP / JS performance, design patterns and more.

6. WordPress Code Reference

The WordPress code reference helps you learn more about WordPress functions, classes, methods, and hooks.

7. Handbook
The official manual for WordPress plugin developers Whether you’re new to plugin development or WordPress Ninja, this is a great resource for any WordPress developer.it will be able to answer all questions related to the development of plugins.

8. Template Tag Reference Guide

Quick template tag reference guide developed by DBS Interactive to speed up its WordPress development.
If you are unfamiliar with WordPress template tags, this may be a useful tool.

9. WordPress Stack Exchange
A set of questions and answers for all your WordPress development requests. This is a great resource for any developer. Not just the person solving the problem, just looking for a solution, if you know the solution, tell others how to solve it.

10. Generate WP
In Custom Development, We Generate custom code for your WordPress project. You can create codes for custom levels, post types, post status, sidebars, menus, shortcodes and more. Most importantly, you don’t have to worry about WordPress coding standards.

We also a Team of Expert WordPress Developers if you have any queries about WordPress feel free to contact us.